@incollection {MR2436122,
    AUTHOR = {Gon{\c{c}}alves, Etereldes and Mathew, Tarek P. and Sarkis,
              Markus and Schaerer, Christian E.},
     TITLE = {A robust preconditioner for the {H}essian system in elliptic
              optimal control problems},
 BOOKTITLE = {Domain decomposition methods in science and engineering
              {XVII}},
    SERIES = {Lect. Notes Comput. Sci. Eng.},
    VOLUME = {60},
     PAGES = {527--534},
 PUBLISHER = {Springer},
   ADDRESS = {Berlin},
      YEAR = {2008},
   MRCLASS = {49M05 (65F10 65N22)},
  MRNUMBER = {2436122},
       DOI = {10.1007/978-3-540-75199-1_66},
       URL = {http://dx.doi.org/10.1007/978-3-540-75199-1_66},
}